Gumby,
I have always found the account of Jephtha disturbing.
However, some commentaries state (and I hope that they are correct) that Jephtha's fullfillment of his vow was not actually offering her as a burnt offering, but that he dedicated her for life for services at the tabernacle (such as Hannah gave up Samuel for temple services). His daughter would have to remain unmarried for the rest of her life.
Also, the rank and file (?) Isralites did not perform their own sacrifices. They had to take their offerings to the priests who performed the actual sacrifice. It would be very hard to imagine a priest that would allow such an abhorrent sacrifice.
Marianne